1. Field of Invention
The present invention relates to a semiconductor device and particularly relates to a semiconductor device capable of storing, erasing, and rewriting data by using an organic compound for a storage circuit. Moreover, the present invention relates to a storage circuit (storage device) capable of storing, erasing, and rewriting data by using an organic compound.
2. Description of the Related Art
In recent years, identification technology where an ID (identification number) is assigned to each object so as to reveal data on the object such as history thereof has been attracting attention, which is utilized for production, management, and the like. Above all, semiconductor devices capable of sending and receiving data without contact have been developed. As such semiconductor devices, in particular, an RFID (Radio Frequency Identification) tag (also called an ID tag, an IC tag, an IC chip, an RF (Radio Frequency) tag, a wireless tag, an electronic tag, or a wireless chip), and the like have been introduced into companies, markets, and the like.
Many of these semiconductor devices currently put into practical use have antennas and circuits using a semiconductor substrate made of Si or the like (such circuits are also referred to as IC (Integrated Circuit) chips), and the IC chip is formed by using a storage circuit (also referred to as a storage device or a memory), a controlling circuit, and the like. In particular, by providing a storage circuit capable of storing a large amount of data, a more sophisticated and higher-value-added semiconductor device can be provided.
In general, the following is given as a storage circuit (storage device) to be provided to a semiconductor device: a DRAM (Dynamic Random Access Memory), an SRAM (Static Random Access Memory), an FeRAM (Ferroelectric Random Access Memory), a mask ROM (Read Only Memory), an EPROM (Electrically Programmable Read Only Memory), an EEPROM (Electrically Erasable and Programmable Read Only Memory), a flash memory, or the like. Among these, a DRAM and an SRAM are volatile storage circuits; therefore, once the power is turned off, data is erased. Accordingly, data needs to be written every time the power is turned on.
Among nonvolatile memories, users can freely write and erase data in an EPROM, an EEPROM, a flash memory, and an FeRAM. With the progress of information technology in recent years, memories capable of storing, erasing, and reading a larger amount of data at high speed have been demanded, and size reduction, cost reduction, and integration of nonvolatile memories have been important issues. However, an EPROM has a drawback that UV rays need to be used to erase data. Although an EEPROM and a flash memory are nonvolatile storage circuits, since an element including two gate electrodes is used, the number of manufacturing steps increases. In contrast, since an FeRAM uses a ferroelectric thin film material and a material and a process that are used for a Si process can be used for an FeRAM, an FeRAM is superior in its characteristics and also has potential to be manufactured at low cost. However, there has been a delay in practical application of this FeRAM, resulting from technical difficulty in thinning a ferroelectric film.